After the end of American Civil War, various state and local organizations were formed for veterans to network and maintain connections with each other. Many of the veterans used their shared experiences as a basis for fellowship. Groups of men began joining together, first for camaraderie and later for political power. Emerging as most influential among the various organizations during the first post-war years, was the Grand Army of the Republic, founded on April 6, 1866, on the principles of "Fraternity, Charity and Loyalty," in Decatur, Illinois, by Dr. Benjamin F. Stephenson.

The G.A.R. initially grew and prospered as a "de facto" political arm of the Republican Party during the heated political contests of the Reconstruction era. The commemoration of Union Army and Navy veterans, black and white, immediately became entwined with partisan politics. The G.A.R. promoted voting rights for then called "Negro"/"Colored" black veterans, as many white veterans recognized their demonstrated patriotism and sacrifices, providing one of the first racially integrated social/fraternal organizations in America. Black veterans, who enthusiastically embraced the message of equality, shunned black veterans' organizations in preference for racially inclusive/integrated groups. But when the Republican Party's commitment to reform in the South gradually decreased, the G.A.R.'s mission became ill-defined and the organization floundered. The G.A.R. almost disappeared in the early 1870s, and many state-centered divisions - named "departments" and local posts ceased to exist.[2]

In his General Order No. 11, dated May 5, 1868, first G.A.R. Commander-in-Chief, General John A. Logan declared May 30 to be Memorial Day (also referred to for many years as "Decoration Day"), calling upon the G.A.R. membership to make the May 30 observance an annual occurrence. Although not the first time war graves had been decorated, Logan's order effectively established "Memorial Day" as the day upon which Americans now pay tribute to all our nation's war casualties, missing-in-action, and deceased veterans. As decades passed, similarly-inspired commemorations also spread across the South as "Confederate Memorial Day" or "Confederate Decoration Day", usually in April, led by organizations of Southern soldiers in the parallel United Confederate Veterans.[3]

In the 1880s, the Union veterans organization revived under new leadership that provided a platform for renewed growth, by advocating Federal pensions for veterans. As the organization revived, black veterans joined in significant numbers and organized local posts. The national organization, however, failed to press the case for similar pensions for black soldiers. Most black troops never received any pension or remuneration for wounds incurred during their Civil War service.[4]

The G.A.R. was organized into "Departments" at the state level and "Posts" at the community level, and military-style uniforms were worn by its members. There were posts in every state in the U.S., and several posts overseas.[4]

With membership strictly limited to "veterans of the late unpleasantness," the GAR encouraged the formation of Allied Orders to aid them in various works. Numerous male organizations jousted for the backing of the GAR, and the political battles became quite severe until the GAR finally endorsed the Sons of Union Veterans of the Civil War as its heir. Although a male organization, the GAR admitted its sole woman member in 1897. Sarah Emma Edmonds served in the 2nd Michigan Infantry as a disguised man named Franklin Thompson from May 1861 until April 1863. In 1882, she collected affidavits from former comrades in an effort to petition for a veteran's pension which she received in July 1884. Edmonds was only a member for a brief period as she died September 5, 1898; however she was given a funeral with military honors when she was reburied in Houston in 1901.[5]

The GAR reached its largest enrollment in 1890, with 490,000 members. It held an annual "National Encampment" every year from 1866 to 1949. At that final encampment in Indianapolis, Indiana, the few surviving members voted to retain the existing officers in place until the organization's dissolution; Theodore Penland of Oregon, the GAR's Commander at the time, was therefore its last. In 1956, after the death of the last member, Albert Woolson, the GAR was formally dissolved.[2]

Modesto, California: Memorial lot in Modesto Pioneer Cemetery contains 36 graves, a wooden cenotaph and two cannons were erected as a monument in 1907. The wooden cenotaph was replaced with a granite obelisk in 1924.[9]

Des Moines, Iowa: In 1922, a banner created for the GAR encampment was declared a permanent memorial and suspended in the rotunda of the Iowa State Capitol.[25] A sundial was dedicated to the GAR on grounds of the Iowa State Capitol during the 1938 encampment.[26]

Red Oak, Iowa: GAR memorial of a bronze soldier atop a granite base was dedicated in 1907 near grave sites in Evergreen Cemetery.[27]

Waterloo, Iowa: The Grand Army of the Republic meeting hall has been restored and is operated as a meeting hall and museum by the City of Waterloo. It was added to the National Register of Historic Places in 1988.[30][31]

Topeka, Kansas: The GAR Memorial Hall at 120 SW 10th Avenue was dedicated May 27, 1914, housed the Kansas State Historical Society until 1995 when the society moved to larger quarters. After restoration, the structure became home to the Attorney General and Secretary of State offices in 2000.[33]

Rockland, Massachusetts: Hartstuff Post 74 was dedicated January 30, 1900. Portions of the wooden structure were restored between 1990 and 1999 and the structure is currently home of the Sons of Union Veterans of the Civil War Camp 50.[37]

Algonac, Michigan: Bronze statue of a soldier on a granite base was erected in 1905 in Boardwalk Park on St. Clair River Drive.[38]

A monument of Whitney granite on a base of the same was erected in 1893 in Pine Ridge Cemetery in a section dedicated as Soldier's Rest. Pine Ridge Cemetery is located on the SE corner of Tuscola and Ridge Rd[39]

In 1902, an 8-inch Howitzer siege gun cannon was added to the Soldier's Rest section of Pine Ridge to guard the soldiers.[40]

Detroit, Michigan: Grand Army of the Republic Building was completed in 1890 as a meeting place for the local chapter of the GAR. When membership dwindled in the 1930s, the group deeded the property to the City of Detroit who paid a portion of the construction costs. The building was listed on the National Register of Historic Places in 1986 and was vacant for many years.[41] In November 2011, the software company Mindfield acquired the building and, through the summer of 2013, spent over $1,000,000 on restoration.[42] In addition to Mindfield, the building now houses an upscale restaurant.[43]

Grand Meadow, Minnesota: GAR Hall/Museum. Booth Post No. 130 was once a meeting hall for members of the Grand Army of the Republic. The hall is believed to be one of only two remaining in Minnesota and is located on South Main Street between First Avenue SW and Second Avenue SW. The building is on the National Register of Historic Places because of its architectural and social significance.[49]

Hastings, Minnesota: Peller Post 89 purchased one-half acre of land for a cemetery in 1905. It holds graves of Civil War and Spanish–American War veterans.[50] In 1998, local VFW post 1210 restored the cemetery.[51]

St. Paul, Minnesota: A memorial obelisk capped by a bronze statue stands at the intersection of John Ireland Boulevard and Summit Avenue. The statue gazes toward the capitol building to the east and was erected in 1903 at a cost of $9,000. It was created by artist John K. Daniels and bears a dedication to "Josias R. King the first man to volunteer in the 1st MN infantry" and commemorates all who fought.[52]

Carthage, Missouri: Park Cemetery contains a lot with several burials from the Stanton Post No. 16 with a large granite monument[53]

Toms River, New Jersey: Monument at Wellington Avenue and Oakdale Street consisting of a small peristyle, flagpole and two cannons [60]

Washington, New Jersey: Inscribed windows commemorating the John F. Reynolds GAR Post 66 donated during construction of the First Methodist Episcopal Church (now The United Methodist Church in Washington) in 1896.

Carnegie, Pennsylvania: When the Andrew Carnegie Free Library and Music Hall was constructed in 1901, it included a room to house the Captain Thomas Espy Post Number 153 of the GAR. The room is now preserved with artifacts and records left when the last post member died in the 1930s.[70]

Titusville, Pennsylvania:, The original charter and other documents from Cornelius S. Chase Post 50, including its handwritten by-laws, are on display at the Cleo J. Ross Post 368 American Legion in Titusville.

Snohomish, Washington: GAR Morton Post 110 established Grand Army of the Republic Cemetery was established in 1889 at 8602 Riverview Road. It contains the graves of 200 Civil War veterans.[77] On May 29, 1914, the community dedicated a monument at the northwest corner of the cemetery consisting of an obelisk and statue of a soldier on a base.[78]

Tacoma, Washington: Oakwood Hill Cemetery has large section containing several hundred GAR veterans who were members of the Custer Post and their wives.[79]

Columbus, Wisconsin: A bronze figure of a soldier atop a square granite column was erected by the H.M. Brown Post 146 of the GAR at the intersection of West James Street (Highway 60) and Dickason Boulevard (Highway 16), adjacent to the City Hall.[80]

With the exception of Hawaii, every state had GAR "posts" (forerunners of modern American Legion Halls or VFW Halls), even those of the former Confederacy. The posts were made up of local veterans, many of whom participated in local civic events. As Civil War veterans died or were no longer able to participate in GAR activities, posts consolidated or were disbanded.[83] Posts were assigned a sequential number based on their admission into the state's GAR organization, and most posts held informal names which honored comrades, battles, or commanders; it was not uncommon to have more than one post in a state honoring the same individual (such as Abraham Lincoln) and posts often changed their informal designation by vote of the local membership.

Many states held annual encampments based on the national encampment model. These state encampments filled both a social and political function, as state GAR leaders were elected, political platforms voted upon, and veterans' issues were discussed openly. Much like the national organization, state GAR leaders could wield strong political influence.

John Steinbeck's East of Eden features several references to the Grand Army of the Republic. Despite having very little actual battle experience during his brief military career, cut short by the loss of his leg, Adam Trask's father Cyrus joins the GAR and assumes the stature of "a great man" through his involvement with the organization. At the height of the GAR's influence in Washington, he brags to his son:

“

I wonder if you know how much influence I really have. I can throw the Grand Army at any candidate like a sock. Even the President likes to know what I think about public matters. I can get senators defeated and I can pick appointments like apples. I can make men and I can destroy men. Do you know that?

”

Later in the book, references are made to the graves of GAR members in California in order to emphasize the passage of time.[84]

The GAR is referenced in John McCrae's poem He Is There! which was set to music in 1917 by Charles Ives as part of his cycle Three Songs of the War.[90]

In Ward Moore's 1953 alternate history novel Bring the Jubilee, the South won the Civil War and became a major world power while the rump United States was reduced to an impoverished dependence. The Grand Army of the Republic is a nationalistic organization working to restore the United States to its former glory through acts of sabotage and terrorism.[91]